The rare move followed calls by Democratic leaders in the House and Senate for a swift inquiry earlier Sunday, questioning whether the GOP leadership in the House had improperly squelched concerns about former Rep. Mark Foley's contacts with pages.

FBI spokesman Richard Kolko said the bureau was looking into whether any federal laws have been violated in the matter, but he had no further comment.

The Florida Republican resigned Friday amid scrutiny of his e-mail and instant-message contacts with pages. The six-term Florida congressman was co-chairman of the Missing and Exploited Children's Caucus and a prominent backer of legislation to crack down on online predators and criminalize child pornography on the Internet. (Watch how politics inspired Foley at age 6 -- 2:44)

The House voted to launch an investigation of his dealings with pages. But in a letter to Attorney General Alberto Gonzales, Hastert urged the Justice Department to look into who knew about the content of any sexually explicit messages involving Foley "and what actions such individuals took, if any, to provide them to law enforcement."

"I request that the scope of your investigation include any and all individuals who may have been aware of this matter -- be they members of Congress, employees of the House of Representatives or anyone outside the Congress," Hastert wrote. (Watch why the Speaker wants an investigation -- 2:34)

Justice Department spokesman Brian Roehrkasse said the department will review "whether we can conduct an investigation."

Hastert, an Illinois Republican, also asked the Justice Department and Florida Gov. Jeb Bush to investigate whether the former lawmaker violated federal or state law.

Earlier Sunday, White House Counselor Dan Bartlett said he expected a criminal investigation. The administration was unaware of the Foley allegations until last week, he said.

"The White House and the president were just as shocked as everyone else," Bartlett said on CNN's "Late Edition."

Top House Republicans have said they were aware months ago of e-mail contact between Foley and a teenage male page, but that they had no knowledge of sexually explicit messages that have subsequently come to light.

Senate Minority Leader Harry Reid said the case should not be handled by the Republican-led Congress.

"Under laws that Congressman Foley helped write, soliciting sex from a minor online is a federal crime," the Nevada Democrat said. "The alleged crimes here are far outside the scope of any congressional committee."

House Minority Leader Nancy Pelosi said House Republican leaders knew of the Foley allegations and "chose to cover it up rather than to protect these children."

In a letter to the leaders of the Ethics Committee, the California Democrat said that GOP leaders should be questioned under oath immediately and that a preliminary report should be issued within 10 days.

After Hastert's request for an investigation, she said the Ethics Committee still needs to look into the actions of the GOP leadership. "Congress must not pass the buck on investigating this cover-up," she said.

Rep. Christopher Shays, a Connecticut Republican, also called for an investigation of his party's leadership.

"If they knew or should have known the extent of this problem, they should not serve in leadership," Shays said Sunday.

Too graphic to report

In a brief resignation statement, Foley apologized to his own family and constituents but did not mention the allegations. He has made no public comment since his resignation.

After the e-mails were publicized, ABC News released instant text messages allegedly sent by the congressman to other teenage male pages in 2003. (More details)

The chamber's three top Republicans -- Hastert, Majority Leader John Boehner of Ohio and Majority Whip Roy Blunt of Missouri -- said in a joint statement Saturday that Foley's "improper communications" were "unacceptable and abhorrent."

Foley had been favored to defeat Democratic candidate Tim Mahoney and win re-election to a seventh term.

"The Republican leadership knew this was going on, and they had to make a choice," Mahoney said. "They decided to try to hold on to a seat."

Reynolds informed Hastert

Rep. Tom Reynolds said over the weekend that he told Hastert about the initial complaint -- that Foley had been e-mailing a 16-year-old Louisiana boy who had served as a page, asking for a picture of the teen and asking what he wanted for his birthday.

The New York Republican chairs the National Republican Congressional Committee, which is the election campaign arm for House Republicans.

Reynolds said that when Rep. Rodney Alexander, a Louisiana Republican, told him about the e-mails, he said the teen's parents didn't want the matter pursued. Alexander was the boy's sponsor.

After an initial denial, Hastert's office said Reynolds brought up the issue of the e-mails in a meeting with the speaker earlier this year.

Reynolds told Hastert in that meeting an investigation had been done by Rep. John Shimkus and the clerk of the House, who manages the work-study program for youths under 18. Shimkus is an Illinois Republican and chairman of the House Page Board.

Rep. Dale Kildee, the only Democratic member of the House Page Board, insisted Saturday the board did not investigate Foley.

Boehner learned about allegations against Foley from Alexander in the spring, said Kevin Madden, the majority leader's spokesman.

Murtha: Finish probe before elections

Shimkus said Foley told him he was only mentoring the teen in the first complaint and was concerned about his fate after Hurricane Katrina.

Shimkus said he warned Foley "to cease all contact with this former House page" -- and he said Foley assured him the e-mails would stop.

The actions taken against Foley were not sufficient, Democrats said Sunday.